Fluid pressure control apparatus for rotary well drilling equipment



March 16, 1954 R. R. STEVENS FLUID PRESSURE CONTROL APPARATUS FOR ROTARY WELL DRILLING EQUIPMENT 3 Sheets-Sheet 1 Filed June 5, 1948 FIG. I

INVENTOR. ROY R. STEVENS AT TORNEY March 16, 1954 R. R. STEVENS FLUID PRESSURE CONTROL APPARATUS FOR ROTARY wELL DRILLING EQUIPMENT 5 Sheets-Sheet 2 Filed June 5, 1948 NDE n n jDu INVENTOR. ROY R. STEVENS BY gl ATTORNEY March 16, 1954 R STEVENS 2,672,222

FLUID PRESSURE CONTROL APPARATUS FOR ROTARY WELL DRILLING EQUIPMENT Filed June 5, 1948 3 Sheets-Sheet 3 INVENTOR. g ROY R. STEVENS lz/zzb AT TORNEY Patented Mar. 16, 1954 UNITED sures TENT OFF] on FLUHD PRESSURE CGNTROL APPARATUS FOR ROTARY WELL DRILLING EQUIP- MERIT Roy R.. Stevens, Forest Hills, Ea, assignor to Westinghouse Brake Gompany, a1 corporation of Pennsylvania Application June 5, 194i8, Serial No. 31,365

over the formation face ineifectively and cause 1:)

undue wear on the bit. If pressure on the bit is excessive, the bit may embed itself in the formation to such an extent that, in an effort to cut itself free, it will chatter up and down as it revolves, thus causing undue wear and strain on the drilling equipment which may result in premature failure of parts thereof. For a given formation and a given speed of rotation of a particular bit, a proper bit pressure may be chosen.

that will give best results. 9.

The driller, in operating the conventional rotary drilling equipment in a well-known manner, intermittently releases a mechanical brake on the hoisting drum for a short interval to allow supporting cable to intermittently-feed from said drum' for effecting periodic increases in bit pressure as the desired bit pressure works off. Dependent upon the at ention of the driller, such intermittent feeding results in excessive fluctuations in hit pressure, resultingin erratican'dinefficient drilling. operation, and it is therefore a prime object of the invention to provide means in the form of fluid pressure control apparatus for controlling operation of the brake on the hoisting drum in such a manner as will eliminate undesired fluctuations in bit pressure.

The present invention takes advantage of the extreme accuracy with which graduations in brake application force may be effected by means of fluid pressure brake apparatus. of a hand operated fluid pressure valve device of the self-lapping, type, variations in pressure of fiuid in a brake cylinder device operatively connected to a brake on the draw works hoisting drum may be effected and maintained for accurately controlling the degree of application of said brake. Consequently, feed of the supporting, cable from the hoisting drum during. drilling may be accurately controlled and in such a manner that said feed may be substantially constantv rather than intermittent, with the result that a substantially constant pressure on the drilling bit maybe maintained without necessity for numerous feed re-adjustments by the driller whose attention then may be directed elsewhere.

By provision During operations involving running drill pipe and/or casing, etc., in and out of the hole, a foot operated valve device is provided in the fluid pressure control apparatus for controlling opera-- tion of the draw Works hoisting drum brake, while leaving the drillers hands free for manipulating shift levers or the like. The foot opera-ted valve device and the hand operated valve device are arranged in parallel, so that, if desired; the driller may remove his foot from the foot operated valve, which will return to brake release position, yet maintain the draw Works drum brake applied by positioning the hand operated valve device.

The invention further provides the fluid pressure control apparatus with novel emergency means for elfecting'either automatic or intentional emergency application of the brake on the draw works hoisting drum in event'of accidental ass in pressure of fluid in, the normal source of supply of fluid under pressure for said apparatus. The emergency means comprises audible signal means, automatically operative upon a certain undesired reduction in the normal supply pressure to sound an alarm forwarning the driller of such condition. Other" objects and advantages will be apparent from the following more detailed description of" the invention taken in connection with the accompanying drawings, in which:

Fig; 1 is an elevation view of parts, of a rotary drilling rig equipment embodying the. invention;

Fig. 2 is a schematic layout, partly in outline and. partly in section, of the control apparatus for the drilling rigv equipment; and

Fig, 3 is a schematic layout substantially in outline of an alternate control apparatus for the drilling rig. equipment.

Description Referring to Fig. I in the drawings, the usual rotary oil or gas. well drilling equipment comprises the rotary bit. I. attached to the lower end.

of the column of drill pipe 2 which is adapted to be rotated by theirotary. table. 3 through the grief stem 4. The lower end of grief stem 4 is attached to the upper'end of the string of drill pipe, while the upper end of said grief stem is carried by the swivel 5'. The swivel 5 allows for rotation of grief' stem, drill pipe, and bit suspended thereby and also serves as aconnector for the flexible mud line 5 through which drilling mud is pumped for supply to the bit. The swivel 5 is carried by the casing hook I which is in turn carried by the traveling" block 8. The traveling block 8- is carried by the supporting cable 9 strung between the traveling block and the crown block In at the top of the derrick (not shown). The dead line H of the supporting cable 9 is anchored, as at l2, to a fixed element, while the opposite end of the cable is wound onto the drawworks hoisting drum l3.

In the well-known manner, during drilling operation with the rotary rig, as the rotary table 3 is rotated by means (not shown), the weight of drill pipe 2 allowed to be exerted by the bit on the bottom of the hole IA is determined by feed of the cable 9 from the drum l3 which is controlled through operation of a band brake l5 which cooperates with a brake drum I9 secured for rotation with the hoisting drum l3 about a central shaft il The usual Martin-Decker type of weight indicator l9 and gauge 26 serves as means whereby the driller or operator of the rig may determine the bit pressure.

According to the principal feature of the invention, I provide a fluid pressure brake cylinder device 2| operatively connected through a lever 22 to the band brake l5. Brake cylinder device 2! is operable by fluid the pressure of which may be controlled by positioning of an operators handle 23 on a self-lapping control valve device 24 or by positioning of a foot pedal 25 on a selflapping control valve device 25. Both control valve devices 26, 26 may be mounted on a control stand 21 of light construction which may be moved to any location convenient for the operator, which location might b that in which it is shown in Fig. 1, adjacent to the draw works drum.

The brake cylinder device 2| may be of the usual construction comprising a hollow cylindrical casing having a piston 28 slidably disposed therein and dividing the interior thereof into a pressure chamber 36 and an atmospheric chamber 3|. A piston rod 32 operatively connects piston 26 with one end of lever 22 the opposite end of which is pivotally connected at 33 to one end of brake band |5. The opposite end of band I5 may be pivotally connected to a fixed element 34. A brake cylinder pipe 35 is provided for conveying fluid under pressure to and from the pressure chamber 39, and a piston return spring 36 is disposed in chamber 3 I.

In operation of the brake cylinder device 2|, when fluid under pressure is supplied to pressure chamber 35 piston 28 will move in the direction of chamber 6| aga nst opposing action of spring 36, causing lever 22 to b rocked about a fixed pivot point 35' and bring brake band l5 into contact with drum I6, whereupon further movement of piston 28 will cease and a braking force will be applied by said band on drum i9 substantially in proportion to the degree of pressure of fluid in chamber 36. Upon release of fluid under pressure from the chamber 30 in brake cylinder device 2|, the return spring 36 will return piston 29, lever 22 and brake band IE to a normal rest or brake release position in which position they are shown in Fig. 1 in the drawings.

Description Fig. 2

Referring to Fig. 2 in the drawings, the preferred form of the fluid pressure control apparatus comprises the self-lapping control valve devices 24, 26 which are operable to effect supply of fluid under pressure from a normal fluid pressure supply pipe 50, common to both, to a control line 5| and to effect release of fluid under pressure therefrom. Delivery from devices 24, 26 is conveyed to control line 5| via respective pipes 52, 53 which are connected to opposite inlets of a double check valve device 54, the outlet of which connects to line 5|, for reasons which will become obvious. Control line 5| is connected to a relay valve device 55 which is operable in response to pressure of fluid in control line 5| to effect supply of fluid at control line pressure from a branch of supply pipe 59 to the brake cylinder pipe 35 via a pipe 55 and a double check valve device 51. Relay valve device 55 may be located adjacent to the brake cylinder device 2|, so that the size and capacity of valve devices 24, 26 and pipes 52, 53 may be considerably reduced over that which may otherwise be required were these required to handle fluid for direct supply to the brake cylinder 2|. It will be appreciated, however, that pipe 5| might be connected to pipe 56 and valve device 55 eliminated insofar as the principle of operation of the control apparatus is concerned.

An emergency protection portion is incorporated in the control apparatus to assure an automatic emergency application of the hoisting drum brake in event of accidental undesired reduction in pressure of fluid in the normal supply pipe 50.

I The protection portion comprises an emergency reservoir 66 adapted to be charged with fluid under pressure from supply pipe 59 via a pipe 6|, two check valve devices 62, arranged therein in series, and a pipe 64. A relay valve device 63 is arranged to control release of fluid under pressure from the emergency reservoir 60 via pipe 64 to double check valve device 51 via a pipe 65 for supply to brake cylinder pipe 35 to effect a brake application. A control pipe 65 is connected to the relay valve device 63 to convey fluid under pressure to and from said device for controlling its operation. A two position control valve device 66 is provided which in one position is arranged to connect pipe 56 to pipe 65 and in its other position to connect pipe 65 to atmosphere. Signal means in the form of a whistle 61 is provided for effecting an audible signal when fluid in the normal supply pipe 59 fall below a certain pressure. A relay valve device 68, similar to relay valve device 63, is arranged to be controlled by pressure of fluid in pipe 56 for controlling communication between pipe 65 and a pipe 69 connected to the whistle 61. A normally open cock 10 is inserted in supply pipe 5!! which is operable to a closed position for cutting oil supply of fluid under pressure from the normal source (pipe 50) to the control apparatus should repair or service to said apparatus be required.

Referring to Fig. 2, the self-lapped control valve device 26 may comprise a casing 1'3 having a fluid pressure supply chamber 13, a delivery chamber I l, and an exhaust chamber '15 therein. A supply valve seat element 16, attached to an operating stem 16 is adapted for reciprocable movement within the casing 12. Element '16 is open intermediate its ends to the supply chamber i3 by way of ports "1! and a central cavity 18, and at its lower end, as viewed in the drawing, to the delivery chamber '15 by way of a supply valve seat l9. A supply valve in the form of a ball may be disposed within cavity 58 for controlling communication between the supply chamber 13 and the delivery chamber M. A bias spring BI is disposed in the cavity ?8 arranged to urge the valve 83 toward a normally closed position on seat 19. An exhaust valve seat element 82, secured for reciprocable movement with deflection of a diaphragm 83, is open at one end to the delivery chamber 14 and has an exhaust valve seat 84 formed therein. Valve seat element 82' extends through the diaphragm 83 with its opposite enddisposed in the exhaust chamber and has a central opening 85 extending from end to end and through the valve seat 84 at the one end. An exhaust valve 85, connected to the supply valve 89 by a pin 80', also in the form of a ball is disposed in delivery chamber 74 to cooperate with theseat 84 in element 82; for controlling communication via opening 85 between said delivery chamber and the exhaust chamber 15; A bias spring 86, disposed in the delivery chamber M, is interposed be tween seat elements 16, 82 for biasing the seat element H5 in the direction of chamber 13. The diaphragm 83 is subject on one side to pressure of fluid in a diaphragm chamber 8?, which pressure of fluid is that of the delivery chamber 74, the two chambers being connected one with the other by way of a choke 83. The opposite side of the diaphragm 83 is exposed to atmosphere by way ofv a port 8% in the casing. A compression control spring 9!! is disposed in the exhaust chamber 15, interposed between the diaphragm and an adjustable spring seat element 9!, for determining the degree of deflection of said diaphragm for any given pressure condition in the delivery chamber 1d. The adjustable spring seat 9| is provided to allow for changing the precompression of the control spring 99.

For effecting adjustment of the stem 76', a cam 93 is provided arranged for turning movement about a fixed shaft 9d by positioning of the operators handle 23 which is secured to said cam. Cain 93 is disposed within a hollow cover cap 534' attached to the top of casing '32. Handle 23 projects outwardly through a slot in cap 8d, and opposite ends of said slot may define extreme stop limits for travel of said handle within said slot.

The cam 93 is so shaped that as handle 23 is rocked from a Release position, in which it is shown in the drawing, to or toward a Full Application position, stem 16' in deviceZ't may be displaced inwardly of casing- ?2 increasing distances in proportion to degree of movement of said handle.

The self-lapping control valve deviceZt is substantially similar to the self-lapping control valve device 2 3, with the exception that position of stem 7% in device '26 is adjusted by means of the foot pedal 25, rather than handle 23 and the cam 95 in device 24. Pedal 25 is arranged for pivotal movement about a fixed pin and is biased toward a normal rest position, in which position it is shown in the drawing, by means of a compression spring 96. As pedal 25 is caused to rock in a counter-clockwise direction about pin 85, stem 16' of device 25 is displaced inwardly of its casing according to degree of the rocking movement of said pedal.

In operation of the self-lapping valve devices 24, 26-, when stem 15' is moved inwardly of the casing 12 a certain distance, the attached seat element 1-8 is moved downwardly, as viewed in the drawing, while the supply valve seat 19 formed in the end of element '16 is moved away from the supply valve 80. At this time, supply valve 88 will remain stationary due to seating engagement of the attached exhaust valve 85' on seat 85 of element 32. After the supply valve seat 19 moves away from the supply valve 80, supply chamber 13 is opened to delivery chamber M by way of ports 1-1, cavity 18 and seat 19. Fluid under pressure from supply pipe 53 connected to supply chamber 13will then flow into the delivery chamber 14 where the pressure of fluid will thus be caused to increase. Pressure of fluid in diaphragm chamber 81 open to cham: ber I l, being greater than the atmosphericprese sure in chamber 15, will deflect diaphragm 83 against action of spring 90 in the direction of, the last mentioned chamber. Deflection of: diae phragm 83- will carry the exhaust valve seatelesment 82 with it. Bias spring 8| will cause the supply valve and exhaust valve 85" to follow movement of element 82, while said exhaust valve remains seated on seat 64 in the. end of said element, until said supply valve seatspon seat is in element it. Upon seating of the sup ply valve 8%, the supply chamber 13 is closed". to the delivery chamber M and further increase in pressure in the latter chamber thereby will. be prevented. In absence of further increase. in delivery pressure in the diaphragm chamber 87!. the pressure force on its one side Will balance with the spring force on its opposite sideand further deflection of said diaphragm will cease. The supply valve 88 and the exhaust valve 8'5. will remain seated. If, at this time, stem 16 were moved inwardly a greater amount, element it would again be moved downwardly to unseat from the supply valve 89, and the above described action would repeat, and an increase; in pressure of fluid would be secured in the; delivery chamber id. The pressure of fluid thus obtained in the delivery chamber 1.4. will. v lid! in substantial proportion to the degree of' ine ward movement of the operating stem 16-. The minimum pressure which will be held in the delivery chamber "i i will depend on thedesr e 9f ire-compression of the control spring 9,0,, which precompression may be changed by adjustment of the spring seat element 9 i.

If, subsequently, the operating stem l6, isralilowed to be moved outwardly of casing 72 lord? tion of spring 85 to a more extended position, the supply valve Bil and attached exhaust valve 85.. will be carried with it. The exhaust valve; 85 is thus unseated from seat 84 in element'82,-and the delivery chamber 14' is thereby opened byway of opening 85 in said element to the exhaust chamber 15. Delivery-pressure in chamber 14 is thus caused to reducaand such reduction ree flected in the diaphragmchamber 81, a11owsthe control spring 96 to deflect the diaphragm 6311p,- wardly. Upward deflection of the diaphragm 83 carries the element 82 into engagement with the exhaust valve 85. The delivery chamber M is thus closed off from the exhaust chamber 15 and further reduction in delivery pressure thereby will be prevented. Under such condition, the die aphragm 83 ceases further deflection, and both th supply valve 86 and the exhaust valve 85' re main seated. A reduced delivery pressure, deter,- mined by position of the operating stem 'I.6.",.is thus secured.

Summarizing action of the self-lapping valve devices 24, 25, it will be seen that with the proper adjustment of the spring $8, and with fluidat adequate pressure in chamber E3, the pressureof fluid in the delivery chamber it is determined' b'y position of element 55 as adjusted through positioning of stem it. By efiecting displacement of stem 16' inwardly of the casing 12, pressure of fluid in delivery chamber 14 will be increased in amount proportional to the degree of said displacement. Conversely, as outward movement of stem 16 is effected, the pressure of fluid in the delivery chamber M will be decreased in amount proportional to-degreeof said outward'movement.

In both valved devices 24, 26 a certain outermost limit position of the stems I6 is defined by rest positions of cam 93 and foot pedal 25, respectlvely. The outermost limit position of stem IS in devices 24, 26 corresponds to a certain minimum pressure in delivery chamber 14. Maximum inward displacement of stem I3 calls for maximum delivery pressure. Still further, both the valved device 24, and the valve device 26 is selfmaintaining, i. e., any tendency for increase or decrease in pressure of fluid in delivery chamber I4 out of accord with position of stem I6 is automatically compensated for to prevent such occurrence in manner as aforedescribed.

Delivery chamber I4 in the self-lapping control valve device 24 is connected to the pipe 52, and delivery chamber 14 in the self-lapping control valve device 26 is connected to the pipe 53. The double check valve device 54 may be of any suitable type such as is shown in the drawing comprising a hollow cylindrical casing I closed at opposite ends by cap members IOI, I02 through which pipes 52, 53 are connected, respectively, opening into opposite ends of said casing. Line is connected to a radial opening in casing I09 equi-distant opposite ends thereof. A piston valve element I03 is slidably mounted within casing I00 and is subject opposingly to pressure of fluid in pipe 52 on its one side and to pressur of fluid in pipe 53 on its opposite side. In the wellknown manner, preponderance of pressure in one of the two pipes 52, 53 will cause piston valve element I03 at one side of line 5| to move in the direction of the other of the two pipes to open the pipe 5I via th interior of casing I09 to the pipe with the preponderance of pressure.

- The relay valved evice 55, shown in outline, may be similar to the fluid pressure valve device disclosed and described in detail in United States Letters Patent No. 2,096,491, issued to Ellis E. Hewitt, October 19, 1937, and assigned to the assignee of the present application. For description such a relay valve device reference may be made to the above named Letters Patent. Briefly,

device 55 is operative upon supply of fluid to line ,1.

5| to effect supply of fluid from pipe 50 to pipe 56 at a pressure substantially equal to pressure of the fluid in line 5|, but such supply will be of sufficient quantity to operate brake cylinder device 2I in being supplied thereto via pipe 35. De-

vice 55, briefly, will respond to variations in pressure in line 5I to effect corresponding variations in pressure of fluid in pipe 56, 35 and brake cylinder device 2| connected thereto.

Check valves 62 may be of any suitable construction and they serve to allow flow of fluid under pressure from supply pipe 50 to pipe 64, but prevent back flow of fluid under pressure in the opposite direction. Two of these check valves, rather than only one, are provided arranged in series as an added assurance that back flow will not occur due to leakage.

The relay valve devices 83, 68 may comprise a casing H3 having a diaphragm H4 disposed therein and subject to pressure of fluid in a diaphragm chamber I I5 on one side and to pressure of fluid in a chamber H6 on its opposite side, which latter chamber is open to atmosphere via a. port I II in the casing. Also formed in the casing are chambers H8, H9 and I20, chamber HS being separated from chamber H6 by a partition I2I and from chamber H9 by a partition I22. A partition I23 separates chambers H9, I20. A supply valve I24 is disposed in chamber I29 for controlling communication between said chamber and the chamber H9. Valve I24 may be secured to a fluted stem I25 slidably mounted in a suitable bore extending through the partition I23, a seat being formed in one end of said bore to accommodate said valve. A bias spring I28 is disposed in chamber I20, arranged to urge the valve I24 in the direction of its seat. A release valve I29, similar to valve I24, is disposed in chamber II8 for controlling communication between said chamber IIO and the chamber H9. For slidably guiding valve I29, a fluted stem I30 is provided which is slidably disposed in a suitable bore opening through partition I22. A valve seat is formed in partition I22 for accommodating the valve I29. Stems I25, I30 project into and meet in the chamber I I9 in such a manner that action of bias spring I28 on valve I24, in urging same in the direction of its seat, at the same time, through said stems, urges valve I29 in a direction away from its respective seat. If valve I29 is seated, valve I24, consequently, will be unseated. Valve I29 is operably connected to the diaphragm H4 by means of a rod or stem I33 extending therebetween through a bore in partition I2I in which said rod is slidably disposed. A control spring I36 is provided in chamber H6, arranged to oppose deflection of the diaphragm H4 in the direction of chamber H8 as caused by pressure of fluid in chamber H5 for determining the degree of said pressure necessary for effecting operation of valves I24, I29.

In operation, the relay valve device 63 and the relay valve device 53 will respond to a certain pressure of fluid in the diaphragm chamber H5 to close valve I29 and open valve I24 to connect the chamber I I9 to chamber I20 hence to atmosphere via a port I20. Upon a subsequent certain reduction in pressure of fluid in diaphragm chamber H5, relay valve devices 63, 68 will respond to close valve I24 and to open valve I29 to connect chamber I I8 to chamber I I9.

In relay valve device 63, chamber H8 is connected to pipe 64, chamber H9 to pipe 65 and diaphragm chamber I I5 to pipe 65.

In relay valve device 68, chamber H8 is connected to pipe 65, chamber H9 to pipe 69 and diaphragm chamber H5 to pipe 50.

The two position control valve device 68 may compris a casing I35 having a delivery chamber I36 formed therein. Chamber I39 is constantly open to pipe 65. A double acting valve element I3! is disposed in chamber I36 and is operable to one position, in which it is shown in the drawing, to cooperate with a seat I30 to close said i. chamber to an atmospheric port I39 while said chamber remains open to pipe 59, and operable to another position away from seat I38 to an oppositely disposed seat I40 for closing ofi pipe 50 from chamber I35 and opening said chamber to atmosphere via port I39. A spring MI is arranged to urge valve element I31 toward seat I38, and an attached stem I42 and cam I43 are arranged so that as said cam is rocked in a counterclockwise direction about a fixed pin I44, as viewed in the drawing, said valve element is displaced through slidable movement of said stem to its other position in sealing engagement with seat I40. Cam I43 may be disposed within a hollow cap member I secured to the top of casing I35 to which pin I44 is attached at its opposite ends. An operators handle I46 is attached to cam I43 for rocking same. Handle I46 may project outwardly through a slot in cap member I45 to render said handle accessible, while opposite ends of said slot may serve as stop limits to define the 9 .two opposite Safety and Emergency Applica tion positions of the valve device, respectively, indicated by dot and dash lines in the drawing and so titled.

In operation of valve device 65, in Safety position of handle in which position it is shown in the drawing, pipe is connected to supply pipe in Emergency Application position, said pipe is connected to atmosphere.

Operation employing control apparatus shown Fig. 2

Referring to Figs. 1, 2 in operation of the rotary rig assume that the column of drill no 2 and bit I are being run into the hole ore atory to drilling. Assume further that in the control apparatus shown in Fig. 2 the control supply pipe 50 is charged with fluid under pressure from a suitable source such as a su ply reservoir 5%, handle Hill of valve device 66 is in "Safety position with pipe 55 consequently connected to supply pipe Relay valve device 53 will be positioned in res use to pressure or fluid in pipe 65 to out off p 3 3 in n pipe 65' which latter pipe will be vented to atmosphere, while relay valve device will be positioned, in response to pressure of fluid in pipe 59, to cut off pipe from pipe '39 which is open to atmosphere through whistle 61.

By manipulation of either the handle 23 in valv device 24 or foot pedal in valve de ce 25, pressure of fluid supplied to the brake c n der device 2! via relay valve device is regulated to control rate of descent of th drill pipe 2 and hit I through control of braking on the hoisting drum i3. While the bit I is yet of? the bottom. of the hole i i, the operator or driller will note the total weight suspended by the supporting cable 9 by observing the weight indicator dial 20. When the bit l res .s on bottom, it will begin to support part of the weight of the drill pipe 2, which weight will be subtracted from the weight carried by the supporting cable 9, indicated to the driller by a shift in position of the needle on the indicator dial 2d. The rotary table 3 will then be brought into operation to rotate the drill pipe 2, hence the bit 5 on bottom to make hole. Through adjustment of position of handle 23 in the selflapping control valve device 24, the degree of pressure provided in brake cylinder device 2!, hence the degree of brake application on the draw works hoi ng drum and hence feed of the cable 9 frosaid drum may be so regulated that the pressure exerted by the bit I on the bottom of the hole 4 as said bit drills through the forma tion may he maintained substantially constant, with little or no attention required by the driller.

For 1e convenience, where intermittent operation of the brakes on the draw works hoisting drum is required, as in making u and breaking joints in running drill pipe or casing in and out of the hole, for example, the foot operated self-lapping control valve device 23 may be employed by the driller, thus leaving both hands free to manipulate, clutch controls, speed controls, or the i although, if desired, the control valve e 24 may be employed for this purpose.

It be convenient for the driller to employ the hand operated self-lapping control valve device 24 and the foot operated self-lapping control valve device 25 together. The control valve device 24 may he set, by positioning handle 23, for a certain brake cylinder pressure to give restraining to the hoisting drum as successive stands of drill pipe are run into the hole, for example, while stops at the end of travel could be effected through operation of the foot operated self-lapping control valve device to effect an increase in brake cylinder pressure above that set by said control valve device 2 5.

Assume that normally the pressure of fluid in the control supply pipe it will vary in a range between one hundred twenty pounds and one hundred fifty pounds, as might be the usual case were said pipe connected to a reservoir supplied by a compressor controlled by a pressure governor, wherein the governor would automatically start the compressor when pressure in the reservoir fell to one hundred twenty pounds and automatically stop the compressor when reservoir pressure reached one hundred fifty pounds.

Now assume that pressure of fluid in the control supply pipe to drops below one hundred twenty pounds, due to failure of the compressor to operate, for example. When such pressure reaches some value such as one hundred ten pounds, such reduced pressure, reflected in the diaphragm chamber of relay valve device 68 will render said device responsive to connect the pipe 35 to the pipe 59. Fluid under pressure from supply pipe 5i) will flow through valve device 65, which is normally in its Safety position, through the branches of pipe 65, through relay valve device 88 and pipe 69 and into whistle ill to sound same and thereby indicate to the driller that supply pressure is below normal. The driller may then eifeet an intentional emergency application of brakes on the draw works hoisting drum !3 by moving handle its on valve device to Emergency Application position to thereby cut off supply pipe from pipe 65 and to connect the latter pipe to atmosphere. Fluid under pressure from diaphragm chamber H5 in relay valve device 63 will now flow to atmosphere via pipe and valve device 66, and when pressure of fluid in said pipe is completely exhausted, the whistle 67 connected thereto will stop sounding. In response to venting fluid under pressure from its diaphragm chamber N5, the relay valve device 53 will however, assume the position for connecting pipe 5 to pipe 65", at which time, fluid under pressure stored in the emergenc reservoir 50 will flow herethrough. It will be appreciated that fluid stored the emergency reservoir will, at this instant, be at the previous maximum pressure attained by fluid in supply pipe 5!], or the assumed value of one hundred fifty pounds. This fluid at one hundred fifty pounds from reservoir so supplied to one side of double check valve device 51, being greater than any pressure of fluid which could exist on the opposite side of said check valve device at this time due to dwindling supply pressure will displace valve element Hi3 rid flow into the brake cylinder pipe 35, then 0 brake cylinder 2! to eiiect an emergency aplication of brakes on the hoisting drum is.

When the pressure of fluid in the supply pipe 5%! is again restored to a normal value above the one hundred twenty pounds, for chosen example, the driller may return the handle lid on control valve device 55 to its Safety position to again connect pipe 5 to supply pipe 58, whereupon fi d under pressure from the latter will flow into the former and thence to the diaphragm chamber H5 in relay valve device 63. Relay valve device will again assume position to disconnect p pe from pipe 65' and connect this latter pipe to the atmosphere. Previously, the relay valve device 68 will have closed oif the p 59 from the pipe 65 when pressure of fluid in its diaphragm chamber II5, connected to supply pipe 55, reached one hundred ten pounds, so that, at time of returning handle I46 in control valve device 66 to its Safety position, the whistle 61 will not sound. A pressure gauge I55 is provided arranged to indicate the pressure condition of fluid in the supply pipe 50 so that by observing same the driller may know when to terminate an emergency brake application.

Now should accidental reduction in pressure in the supply pipe 56 be so rapid as to defy action on the part of the driller to take the above necessary step to effect an intentional emergency brake application, same will be effected automatically. When pressure of fluid in supply pipe 50 drops below one hundred ten pounds, relay valve device 68 will respond, in manner previously described, to connect pipe 69 to pipe 65 to blow Whistle 57. As failure of supply pressure continues and drops below some value such as eighty pounds the relay valve device 63 will respond automatically to connect emergency supply of fluid under pressure from reservoir 66 to pipe 65 hence to the brake cylinder device 2I. The pressure of fluid in supply pipe 56 and henc pipe 65 may then drop to atmospheric pressure if a severe break in the pipe should exist, in which case the whistle would naturally cease to sound. However, should some pressure in supply pipe 56 be maintained, though below eight pounds, it may be desirable to intentionally silence the whistle 61, and this may be accomplished by moving handle I45 in valve device 66 to its Emergency Application to vent pipe 55, srpplying fluid under pressure to said whistle, to atmosphere. If handle I46 i in its Emergency Application position when pressure of fluid in supply pipe 56 is restored to normal, normal con.- trol of the brakes is reestablished b returning handle I46 in device 66 to Safety position as previously described. If, however, handle I45 in device 66 is allowed to remain in its Safety position during the automatic emergency brake application, i. e., pipe 65 remains connected to supply pipe 56, then as supply pressure is again built up, the relay valve device 63 will automatically respond to cut off pipe 64 from the pipe 65' and to vent the latter pipe to atmosphere T when supply pressure is increased to eighty pounds. When supply pressure continues to increase to one hundred ten pounds the relay valve device 68, as before, cuts off pipe 69 from pipe 65 to terminate supply of fluid under pressure to the Whistle 61.

Description Fig. 3

shown in Fig. 3 differs from that shown in Fig.

2 in that the emergency portion of the control apparatus is adapted and arranged to employ a spring I55 for effecting emergency application of the brake on drum I3. Connection of brake cylinder device 2| with the brake band I5 is altered slightly to incorporate the spring I55. Piston rod 32 may be pivotally connected to one end of a brake cylinder lever I56. The opposite end of lever I56 may be pivotally connected at I51 to a fixed element I58 and the live end of brake band I5 connected at I59 to said lever intermediate its ends. Clockwise turning movement of lever I56 about pin I57, as viewed in the drawing, will effect tightening of band i5 about brake drum :6 attached to hoisting drum I3. Turning movement of lever I56 in the opposite direction will effect release of the brake. Degree of any normal brake application, as before, will depend upon the pressure of fluid supplied to pressure chamber 36 in brake cylinder device 2I.

The emergency application spring I may encircle a rod I66 slidably mounted at its one end in a bore in a fixed element I6I and attached at its opposite end to a piston I62 slidably mounted within a cylinder I63 mounted on a fixed element I64. One end of spring I55 abuts fixed element IBI while its opposite end abuts an annular stop member I65 attached to rod I60. By maintaining fluid in a brake cylinder pressure chamber I66, at one side of piston I62 and connected to pipe 65 spring I55 is held in compression. During normal operation of the control apparatus, the piston I62 and rod I are so disposed as to hold spring I55 compressed beveen stop member I and fixed element IGI. A groove I6? is formed in rod I60 intermediate its ends in which a pin I68 carried by lever I56 projects. The groove I6? is of sufficient width and length as to allow for movement of lever I56 during normal operation of the hoisting drum brake by the brake cylinder device 2|. A shoulder I69 formed at one end of groove I6! is provided for engagement with pin I68 to transmit force to the lever I56 for efiecting an emergency brake application as spring I55 is allowed to expand against member I65 when fluid under pressure is vented from brake cylinder pressure chamber I66. As was not true, therefore, in regard to operation of the emergency portion of the control apparatus shown in Fig. 2, an emergency brake application is efiected by venting fluid under pressure from pipe 65 rather than supply thereto. This is provided for by changing two connections in the relay valve device 63; pipe 50 is connected to chamber I20, and pipe 64, previously connected to reservoir 60, is disconnected therefrom and opened to atmosphere. Now, as pressure of fluid in pipe 65 is normally maintained above eighty pounds, relay valve device 63 will maintain pipe 65', hence chamber I56 in brake cylinder device I63 pressurized, while, if pressure in pipe 65 drops below eighty pounds, relay valve device 63 will vent said chamber I66 to atmosphere via pipe 65 t effect an emergency brake application. Device 66, 66 and whistle 61 function as aforedescribed.

Summary It will be seen now that I have provided fluid pressure control apparatus arranged to be associated with a draw works hoisting drum brake for controlling certain operations connected with a rotary drilling rig which will assure a substantially constant pressure of the drilling bit exerted against a given formation, thus eliminating the erratic and inefficient method previously employed. The control apparatus provides for flexibility of operation in handling drill pipe, casing, etc., in running in and out of the hole and comprises protection means for effecting an emergency application of brakes on the draw works hoisting drum, intentionally or automatically, should pressure of fluid from the normal source of supply accidentally reduce below a desirable value. Signal means in the form of a whistle is arranged for automatic operation upon such accidental reduction in supp-1y pressure to indicate the condition to the driller. Means are provided whereby the signal may be intentionally rendered inoperable, if desired, when in operation and said means so arranged that once the control apparatus is again set up for normal control, the signal means is automatically rendered operable.

Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. Apparatus for controlling application and release of fluid pressure controlled emergency brake means. said apparatus comprising a source of fluid under pressure, a first relay valve device adapted for control connection with said brake cylinder device and having a control chamber, said first relay valve device being responsive to variations in pressure of fluid in its control chamber above and below a certain value for effecting release and application, respectively, of said emergency brake means, a signal device rendered effective and inefiective responsively to receipt and termination of receipt, respectively, of fluid under pressure thereto, a second relay valve de vice having a delivery chamber constantly connected to said signal device, a supply chamber, and a control chamber constantly connected to said source, said second relay valve device being responsive to variations in pressure of fluid in its control chamber above and below a second certain value, higher than the first mentioned certain value, to disestablish and establish, respectively, fluid pressure connection between its delivery chamber and its supply chamber, and an operators control valve device having a delivery chamber constantly open to the control chamber in said first relay valve device and to the supply chamber in said second relay valve device, said operators control valve device being operable to connect its delivery chamber selectively to said source or to the atmosphere.

2. Apparatus for controlling operation of emergency brake means having a brake cylinder pressure chamber and being responsive to pressurization and de-pressurization of said brake cylinder pressure chamber to effect release and application, respectively, of a braking force, said apparatus comprising a source of fluid under pressure, a first relay valve device having a supply chamber constantly connected to said source of fluid under pressure, a delivery chamber adapted for constant connection with said brake cylinder pressure chamber, an exhaust chamber constantly open to the atmosphere, and also having a control chamber, said first relay valve device being responsive to variations in pressure of fluid in its control chamber above and below a certain value to connect its delivery chamber selectively to its supply chamber or to its exhaust chamber, respectively, a signal device rendered effective and ineifective responsively to receipt and termination of receipt, respectively, of fluid under pressure thereto, a second relay valve device having a delivery chamber constantly connected to said signal device, a supply chamber, and a control chamber constantly connected to said source, said second relay valve device being responsive to variations in pressure of fluid in its control chamber above and below a certain value, higher than the first mentioned certain value, to disestablish and establish, respectively, fluid pressure connection between its delivery chamber and its supply chamber, and an operators control valve device having a delivery chamber constantly open to the control chamber in said first relay valve device and to the supply chamber in said second relay valve device, said operator's control valve device being operable to connect its delivery chamber selectively to said source or to atmosphere.

ROY R. STEVENS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 989,460 Westphal Apr. 11, 1911 1,187,693 Woolley June 20, 1916 2,109,297 McMurry et a1. Feb. 22, 1938 2,117,078 Brauer May 10, 1938 2,187,969 Grau et a1. Jan. 23, 1940 2,211,890 Farmer Aug. 20, 1940 2,275,255 Freeman Mar. 3, 1942 2,282,615 Spalding May 12, 1942 2,366,310 Boldt Jan. 2, 1945 2,366,608 Freeman Jan. 2, 1945 2,515,946 Cadman July 18, 1950 

